May 26, 2011
FOWLER BAULD MITCHELL LTD.
The curtainwall-clad Halifax Central Library is comprised of a concrete cast-in-place structure on all levels but the top floor, where a steel structure was required to accommodate the eight-metre cantilever.
Halifax Central Library envelope-structure interactions provide challenges
Site excavation of the new Halifax Central Library is off to a slow if not peculiar start. Excavators are scraping four inches of soil off the north end of the site at a time, giving archeologists an opportunity to carefully comb through the material for remnants of historic foundations and artifacts.
In the 1700s, the site was home to Bellevue House, the residence of the British Armys Commander-in-Chief for Halifax, and before that it might have been occupied by local natives. Archeologists will do a detailed search to record, study and preserve any discovered items.
Having a team of archeologists controlling the tempo of construction might be nerve-racking to most builders, but the librarys construction manager isnt losing any sleep over it.
That is because work started a few months early and archeologists are only interested in what lies below one of two lots for the new building.
If they find something of interest on the north lot, well redirect excavation to the south site where there are no restrictions on excavation or construction, says Roland Doucet, construction manager for EllisDon,which is acting as construction manager for the 100,000-square-foot landmark building in downtown Halifax.
The library, which features several glass floors stacked at odd angles to each other, will be a landmark in the citys hub.
The design calls for a ground floor setback on the property while two upper floors hang over a ground-floor plaza by about three metres, says George Cotaras, partner in charge with Fowler Bauld Mitchell Ltd.
The Halifax-based architect is in a joint venture on the library project with Denmark-based Schmidt Hammer Lassen Architects.
The designs most striking feature is the smaller top floor, which makes up some of the lost space with a cantilever of more than eight metres over the lower floors. The interior features a five-storey atrium offering views of various floors twisted on their axis.
To come up with the unusual design, the architect hosted almost half a year of public input meetings in a world cafe format that allowed every attendee a chance to be heard, says Cotaras, pointing out that the process is unusual in Halifax.
At most public meetings an architect stands up in the front of the room and says, lsquo;Heres the design, what do you think? Here, we asked the public what they wanted their library to be.
The curtainwall-clad building is comprised of a concrete cast-in-place structure on all levels but the top floor where a steel structure was required to accommodate the eight-metre cantilever.
The building is targeting a LEED Gold certification. Green features include advanced Low-E glazing and spectrally-selective glass to maximize natural light while minimizing infrared and ultraviolet light. One of the buildings many roofs will be green.
The project will also score at least one LEED point for diverting 50 perc ent of construction waste from landfill. The builder hopes go a step further, diverting an additional 25 per cent a tough target to meet on most projects for an additional LEED point.
Doucet says the big construction challenge will be dealing with the extensive details where the building envelope meets the structure because the building is essentially divided into four buildings, positioned at different angles (like a skewed stack of books) to each other. The many small roofs will require extensive details at penetrations with the envelope.
Its not the body of the roof or the (high-efficiency) curtainwall that were concerned about; its where they transition from one area to another, says Doucet.
The builder says another challenge will be dealing with the shortage of skilled trades mechanical tradespeople are a case in point. Part of the problem stems from an aging workforce nearing retirement but the shortage is exacerbated by a migration of workers west (to Fort McMurray, Alta., for example) where jobs are plentiful and money is good, says Doucet.
To deal with the shortage, rather than set an impossible-to-meet aggressive schedule, EllisDon will meet with its subs to sequence work and in some cases stretch activities in a manner that subs can handle, he says.
The key is to accomplish this without delaying the project.
The library is slated for completion in December 2013.
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